A temperature-sensitive rotator cuff self-locking nerve conduit and its preparation method

Abstract

The present invention provides a temperature-sensitive rotator cuff self-locking nerve conduit and a preparation method thereof, comprising the following steps: preparing a PDMS mold with a micron-scale anisotropic topological geometric structure in the middle and micro-needle hole structures at both ends; sequentially pouring a natural or synthetic biomaterial containing a nerve growth factor and an anti-inflammatory factor into the micro-needle holes on the surface of the PDMS stamp, and air-drying or cross-linking and curing; imprinting a temperature-sensitive hydrogel solution onto the surface of the PDMS stamp, and forming a biomaterial scaffold after cross-linking; peeling the imprinted biomaterial scaffold from the PDMS stamp to obtain a temperature-sensitive rotator cuff self-locking nerve conduit. The present invention adopts a micro-molding technique and a step-by-step casting technique, and the obtained biomaterial scaffold is easy to peel from the PDMS stamp, can maintain a relatively large diameter at room temperature, can rapidly shrink at body temperature after being transplanted into the body to achieve self-locking fixation, the micro-needles can penetrate the nerve membrane to achieve controllable release of the drugs loaded therein inside the nerve, and its micro-structure avoids the negative impact on nerve regeneration caused by traditional surgical suturing.

Description

Technical Field

[0001] The present invention belongs to the field of medical biomaterials implantable in the human body in tissue engineering and regenerative medicine, and particularly relates to a temperature-sensitive rotator cuff self-locking nerve conduit with microneedles and an anisotropic topological structure on the inner wall and a preparation method thereof. Background Art

[0002] According to research reports, up to 1 million people worldwide suffer from peripheral nerve injury (PNI) every year. PNI usually occurs due to trauma, surgical resection, or local drug poisoning, which may lead to severe sensorimotor disorders and chronic nerve pain, imposing a heavy burden on families and society. The peripheral nervous system contains parallel axon bundles sheathed by Schwann cells, and the extracellular matrix also contains an ordered structure composed of various proteins. Therefore, a nerve conduit with an anisotropic topological structure arranged longitudinally can well simulate the microenvironment of natural nerve tissue, and is expected to guide the recruitment of Schwann cells and prompt them to migrate and align along the topological direction, and promote the directional growth and extension of axons to promote the regeneration of peripheral nerves. However, currently, artificial nerve grafts usually have a slightly larger diameter than normal nerves. When repairing defects, the nerve conduit needs to be sutured to the nerve through a suture operation. Although absorbable surgical sutures have been widely used, there is still a risk of scarring or hyperplasia at the suture site, and the nerve will inevitably be damaged to a certain extent during the suture process. The self-locking conduit can self-contract with the change of the surrounding environment, firmly fix at both ends of the severed nerve, eliminate the penetration of the nerve and the excessive local tensile stress, and well eliminate the harm of traditional surgery. Therefore, there is an urgent need to develop a technology for preparing self-locking nerve conduits to reduce the risks brought by traditional surgical sutures, and further improve the fixation stability and the promotion effect on nerve regeneration through the drug-loaded microneedle structure.

[0003] Microneedles (MNs) are an emerging system in recent years, consisting of micron-scale needles and commonly used for transdermal drug delivery, but there is no application in nerve conduits. In current studies of microneedle skin patches, microneedles can not only penetrate the epidermal layer to open the drug delivery channel, but also fix the patch on the skin surface to achieve sustained drug release. Therefore, by adding drug-loaded microneedle structures at both ends of the self-locking nerve conduit, deep delivery of drugs inside the nerve can be achieved, and minimally invasive connection between the conduit and the nerve can be completed, which is a very promising direction. Currently, with the help of microelectromechanical, ion etching, wet etching, photolithography and other technologies, it is possible to well realize micron-scale topologies and precision structures such as microneedles on various inorganic metal and non-metal surfaces, but the structural processing of organic biomaterials is still relatively difficult. Common methods include electrospinning, micro molding, 3D printing, microfluidics, etc. Among them, electrospinning and microfluidics technologies cannot prepare microneedle structures, the orientation of anisotropic topologies needs to be improved, and the process parameters are complex, requiring multiple explorations and adjustments during the application process; 3D printing has low precision and many restrictions on materials, making it difficult to be widely used; while micro molding technology can well overcome the above disadvantages, with variable structures and easy adjustment, and very few requirements for materials.

[0004] Hydrogel is a type of extremely hydrophilic three-dimensional network structure gel. It can rapidly swell in water and maintain a certain volume without dissolving. By changing its water content, controllable adjustment of volume can be achieved, and it has been widely used in tissue engineering. Temperature-sensitive hydrogel belongs to a type of in-situ gel. When the temperature changes, the interaction force and hydration ability of hydrophilic and hydrophobic groups on its molecular chain will be affected, showing volume change or swelling property change. According to the sol-gel phase transition state, hydrogels can be divided into positive temperature hydrogels and negative temperature hydrogels. Positive temperature hydrogels have the upper critical solution temperature (UCST). This gel absorbs water and dissolves at temperatures above UCST and dehydrates and shrinks at temperatures below UCST. Negative temperature hydrogels have the lower critical solution temperature (LCST). This type of hydrogel remains liquid below LCST, while above LCST, the hydrogel undergoes a sol-gel transition, with its structure shrinking and volume decreasing. N-isopropylacrylamide (PNIPA) hydrogel has hydrophilic amide groups and hydrophobic isopropyl groups in its molecule. The interaction between the two makes the gel have good temperature responsiveness. Its lower critical solution temperature LCST is around 33°C, close to the human body's physiological temperature. By changing the ratio of hydrophilic / hydrophobic components (i.e., copolymerizing with hydrophilic monomers such as acrylic acid (AAc)), it can also be adjusted at a temperature slightly higher than the human body temperature and is widely studied in the field of biomedicine.

[0005] In summary, the present invention provides a method for preparing a temperature-sensitive rotator cuff self-locking nerve conduit with microneedles and an anisotropic topological structure on the inner wall. As the temperature of the conduit changes from the storage temperature (~4°C) to body temperature (~37°C), the volume can be reduced by 30%-50%, realizing self-locking fixation of the conduit to the transected nerve. The drug-loaded microneedles on both sides of the inner wall of the conduit can not only achieve deep drug release but also strengthen the fixation effect, avoiding the detachment of the conduit due to sliding. The anisotropic topological structure in the middle part of the inner wall of the conduit can well guide the elongation and migration of Schwann cells and the extension of axons, accelerating the speed of peripheral nerve regeneration and repair. Compared with traditional nerve grafts, the present invention promotes the directional elongation of transected nerves through an anisotropic topological structure, innovatively uses temperature-sensitive biomaterials and adds a microneedle structure, avoiding the negative impacts brought by traditional surgical sutures and realizing deep drug delivery. The usage method is simple and easy, only needing to insert both ends of the transected nerve into the inside of the conduit and waiting for the conduit to shrink and self-lock with the temperature change. Therefore, in view of the vacancy of related products in the market, the present invention has great application value. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing a temperature-sensitive rotator cuff self-locking nerve conduit with microneedles and a micron topological geometric structure on the surface, so as to eliminate the potential risks that may be brought by conventional surgical sutures and solve the problems in the prior art that it is difficult to achieve deep drug delivery and sustained release, and it is difficult to continuously induce long-distance directional growth and regeneration of nerves.

[0007] To solve the above existing problems, the present invention adopts the following technical solutions:

[0008] (1) After fully mixing dimethylsiloxane monomers and cross-linking agents, they are poured into a customized planar or cylindrical mold, and cross-linked after vacuum degassing to prepare a planar or cylindrical elastic stamp, i.e., a PDMS mold, with an oriented micron topological geometric structure in the middle and microneedle hole structures on both sides.

[0009] (2) Different drugs are premixed in a biomaterial solution. The natural or synthetic biomaterials mixed with different drugs are sequentially poured into the microneedle holes on the surface of the PDMS mold by a stepwise casting method. After centrifugation or vacuum pumping to ensure that the holes are completely filled without air, they are air-dried or cross-linked and cured to form the needle structures on both sides of the graft.

[0010] (3) After mixing the temperature-sensitive hydrogel precursor solution and the cross-linking agent, they are poured onto the surface of the PDMS mold and cross-linked to form a biomaterial scaffold.

[0011] (4) The catheter is spontaneously detached from the cylindrical PDMS mold through cooling expansion, or the stent is peeled off from the planar PDMS mold, and the side with the topological structure is curled inward into a tubular structure and bonded to obtain a temperature-sensitive rotator cuff self-locking nerve conduit with a micron-scale topological geometry structure in the middle and microneedle structures on both sides.

[0012] The middle part of the temperature-sensitive rotator cuff self-locking nerve conduit with a micron-scale topological geometry structure on the inner surface described in the present invention is a micron-scale topological geometry structure, and both sides are composed of a micron-scale microneedle array. Preferably, the micron-scale topological geometry structure in the step (1) is one or more array combination modes of anisotropic structures such as micron grooves and ridges, micron concave holes, and micron protrusions; the microneedle structure is one or several of various structures such as cones, pyramids, and arrows, and the microneedles are arranged in one or more array combination modes such as uniform distribution or guiding along a specific direction. Further preferably, the micron-scale topological geometry structure is selected as micron grooves and ridges, the high part is the ridge, the low part is the groove, the vertical distance between the groove and the ridge is 2-10 μm, the width of the groove and the ridge is 10-50 μm, and the connection between the groove and the ridge is smooth or vertical; the microneedles are selected to be uniformly arranged, with a height of 100-1000 μm, the bottom diameter of the microneedles is 100-200 μm, and the tip diameter is 30-50 μm.

[0013] The main body of the tissue engineering graft described in the present invention is preferably a negative temperature-sensitive thermosensitive hydrogel such as poly(N-isopropylacrylamide) (PNIPA) and poly(N,N-diethylacrylamide) (PDEAM), and rapid shrinkage and self-locking can be achieved by heating from the storage temperature to the human body temperature through hot compress or infrared irradiation; the microneedle material composition is preferably one or several of natural or synthetic materials such as hyaluronic acid (HA), methacrylated hyaluronic acid (HAMA), chitosan (CS), silk fibroin (SF), collagen (Col), polycaprolactone (PCL), and polylactic acid (PLA); the microneedles are divided into a needle tip and a base part, and different drugs are respectively loaded by natural or synthetic biomaterials. Preferably, the needle tip is loaded with one or several nerve growth-promoting drugs such as nerve growth factor (NGF), ciliary neurotrophic factor (CNTF), rapamycin (RAPA), and reduced graphene oxide (rGO), and the base is loaded with one or several anti-inflammatory drugs such as triamcinolone acetonide (TA), curcumin (Cur), and oligomeric procyanidins (OPC).

[0014] Preferably, for the nerve conduit prepared by the method of the present invention, the rapid heating method can be infrared radiation, hot compress, etc.

[0015] Preferably, for the nerve conduit prepared by the method of the present invention, its length can be customized from 10 - 50 mm according to actual usage requirements; for its drug release, drugs that need to be released preferentially can be loaded at the tip of the microneedles, and drugs that need to be released subsequently can be loaded at the base of the microneedles, and the drug release rate can be controlled according to the type and degree of crosslinking of the biomaterials used for the microneedles.

[0016] Advantages of the present invention:

[0017] (1) By combining the microneedle structure with the temperature-sensitive hydrogel in the present invention, self-locking and reliable fixation of the nerve conduit with both ends of the damaged nerve can be achieved at body temperature, avoiding problems such as secondary trauma and scar hyperplasia that may be caused by suture surgery.

[0018] (2) The inner wall of the temperature-sensitive self-locking nerve conduit prepared by the present invention has a micron anisotropic topological structure, which can effectively guide the directional migration, growth of Schwann cells and the directional elongation of axons during nerve regeneration.

[0019] (3) The anti-inflammatory drugs and nerve growth-promoting drugs loaded in the microneedle structure of the present invention can effectively inhibit the inflammatory reaction caused by injury, synergistically promote the repair of peripheral nerve injury, and have a good sustained-release effect as the microneedle structure slowly degrades.

[0020] (4) The temperature-sensitive rotator cuff self-locking nerve conduit prepared by the present invention has good biocompatibility, stable biochemical properties, good flexibility, and can be customized in size according to actual needs.

[0021] (5) The present invention can prepare both a biomaterial scaffold with a two-dimensional micron topology and microneedle patterns and an artificial nerve conduit with a three-dimensional micron topology and microneedle patterns. Description of the drawings

[0022] Figure 1 Design diagram of a conduit with an anisotropic topological structure on the inner wall, complete conduit structure (left figure a) and cross-sectional conduit structure (right figure b).

[0023] Figure 2 Design diagram of a conduit with rotator cuff self-locking and an anisotropic topological structure on the inner wall, complete conduit structure (left figure a) and cross-sectional conduit structure (right figure b).

[0024] Figure 3 Schematic diagrams of the temperature-sensitive rotator cuff self-locking nerve conduit before contraction (left figure a) and after contraction (right figure b).

[0025] Figure 4 Schematic diagram of preparing the temperature-sensitive rotator cuff self-locking nerve conduit using the micro-molding technology according to the embodiment of the present invention.

[0026] Figure 5Schematic diagram of the internal structure and composition of the temperature-sensitive rotator cuff self-locking nerve conduit prepared by the micro-molding technique according to the embodiments of the present invention.

[0027] Figure 6 Photo of the planar PDMS mold according to the embodiments of the present invention. There are micro-holes on both sides of the mold, and an oriented topological groove in the middle. This stamp can be reused and is suitable for large-scale stable production.

[0028] Figure 7 Thermal shrinkage photo of the temperature-sensitive rotator cuff self-locking nerve conduit according to the embodiments of the present invention. Figure 4 The conduit shown in the figure is heated from the storage temperature (4 °C) to the human body temperature (37 °C), and the inner diameter of the conduit decreases by about 50%, which can self-lock to achieve effective fixation of the nerve.

[0029] Figure 8 Middle groove structure of the temperature-sensitive rotator cuff self-locking nerve conduit prepared according to the embodiments of the present invention.

[0030] Figure 9 And photos of the micro-needle structures on both sides. Figure 5 、 Figure 6 The groove and micro-needle structures prepared in the figure are highly regular, and the groove has a high degree of orientation. Detailed implementation manners

[0031] The present invention will be further explained below in conjunction with examples. The following examples are only used to illustrate the present invention, but not to limit the scope of implementation of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0032] Example 1

[0033] A temperature-sensitive rotator cuff self-locking nerve conduit with micro-needles and micron topological geometric structures on its surface, and the specific preparation includes the following steps:

[0034] (1) After fully mixing dimethyl silicone monomer and cross-linking agent with a volume ratio of 10:1, it is poured onto a cylindrical polymer mold with micro-needles and anisotropic micron topological structures on its surface. After vacuum degassing for 1-2 h, it is cross-linked overnight in an oven at 60 °C. After full curing, a PDMS columnar mold with a micron topological geometric structure in the middle and micro-needle hole structures on both sides is obtained;

[0035] (2) Dissolve nerve growth factor and curcumin in a 3% chitosan solution at a concentration of 10-100 μg / ml respectively. Use a micro syringe to inject the two solutions into the holes of the PDMS in turn, and centrifuge at high speed for 5 min to ensure complete filling in the holes. After air drying, a needle body structure is obtained;

[0036] (3) Weigh 48 g of N-isopropylacrylamide (NIPA) and 0.6 g of N,N'-methylenebisacrylamide (BIS) into 100 ml of triple-distilled water, stir at room temperature until completely dissolved to obtain a precursor solution; dissolve 1 g of ammonium persulfate (APS) in 10 ml of triple-distilled water to obtain a 10% initiator solution.

[0037] (4) Add 1 ml of the initiator solution to 10 ml of the precursor solution. Place a concentric circular sleeve outside the PDMS columnar mold, and quickly pour the mixed solution between the PDMS mold and the sleeve. After vacuum degassing, crosslink at 80 °C for 1 h.

[0038] (5) Slowly cool down in triple-distilled water. After the temperature-sensitive catheter cools down and expands, the catheter can be automatically removed from the mold, obtaining a temperature-sensitive rotator cuff self-locking nerve catheter with a micron topological geometric structure in the middle and micro-needle structures on both sides.

[0039] (6) When implanting in the body, select a catheter with a diameter slightly larger than the nerve. Insert the two ends of the severed nerve into both sides of the catheter, and use the method of hot compress to quickly heat and contract the catheter to achieve effective fixation of the nerve, and then suture the wound.

[0040] Example 2

[0041] A temperature-sensitive rotator cuff self-locking nerve catheter with micro-needles and micron topological geometric structures on its surface, and its specific preparation includes the following steps:

[0042] (1) After fully mixing dimethylsiloxane monomer and crosslinking agent with a volume ratio of 10:1, pour it onto a cylindrical polymer mold with micro-needles and anisotropic micron topological structures on its surface. After vacuum degassing for 1 - 2 h, crosslink overnight in an oven at 60 °C. After full curing, obtain a PDMS columnar mold with a micron topological geometric structure in the middle and micro-needle hole structures on both sides.

[0043] (2) Dissolve nerve growth factor and curcumin in 3% chitosan solution at a concentration of 10 - 100 μg / ml respectively. Use a micro syringe to inject the two solutions into the holes of the PDMS in sequence, and centrifuge at high speed for 5 min to ensure complete filling in the holes. After air drying, obtain the needle structure.

[0044] (3) Weigh 48 g of N-isopropylacrylamide (NIPA) and 0.6 g of N,N'-methylenebisacrylamide (BIS) into 100 ml of triple-distilled water, stir at room temperature until completely dissolved to obtain a precursor solution; dissolve 1 g of ammonium persulfate (APS) in 10 ml of triple-distilled water to obtain a 10% initiator solution.

[0045] (4) Add 2 ml of initiator solution to 10 ml of precursor solution, add a concentric sleeve to the outside of the PDMS cylindrical mold, and quickly pour the mixed solution between the PDMS mold and the sleeve. After vacuum degassing, crosslink at 80 ° C for 1 h;

[0046] (5) slowly cooling in triple-distilled water, and after the temperature-sensitive catheter cools down and expands, the catheter is automatically removed from the mold to obtain a temperature-sensitive rotator cuff self-locking nerve catheter with a micron topological geometric structure in the middle and microneedle structures on both sides;

[0047] (6) When implanted in the body, the diameter of the selected catheter is slightly larger than the nerve. The two ends of the broken nerve are inserted into the catheter. The catheter is quickly heated and contracted by hot compress to effectively fix the nerve. The wound is then sutured.

[0048] Example 3

[0049] A thermosensitive rotator cuff self-locking nerve conduit with microneedles and micron topological geometric structures on the surface, the specific preparation of which includes the following steps:

[0050] (1) After fully mixing dimethylsiloxane monomer and crosslinking agent in a volume ratio of 10:1, the mixture is poured onto a cylindrical metal mold having microneedles and anisotropic micron topological structures on the surface, vacuum degassed for 1-2 hours, and then crosslinked in an oven at 60°C overnight. After fully curing, a PDMS columnar mold having a micron topological geometric structure in the middle and microneedle hole structures on both sides is obtained;

[0051] (2) Dissolve neurotrophic factors and curcumin at a concentration of 10-100 μg / ml in 3% chitosan solution, inject the two solutions into the pores of PDMS in sequence using a microsyringe, centrifuge at high speed for 5 min to ensure that the pores are completely filled, and air-dry to obtain the needle structure;

[0052] (3) Weigh 48 g of N-isopropylacrylamide (NIPA) and 0.6 g of N,N'-methylenebisacrylamide (BIS) in 100 ml of triple distilled water, and stir at room temperature until completely dissolved to obtain a precursor solution; dissolve 1 g of ammonium persulfate (APS) in 10 ml of triple distilled water to obtain a 10% initiator solution;

[0053] (4) Add 1 ml of initiator solution to 10 ml of precursor solution, add a concentric sleeve to the outside of the PDMS cylindrical mold, and quickly pour the mixed solution between the PDMS mold and the sleeve. After vacuum degassing, crosslink at 80 ° C for 1 h;

[0054] (5) slowly cooling in triple-distilled water, and after the temperature-sensitive catheter cools down and expands, the catheter is automatically removed from the mold to obtain a temperature-sensitive rotator cuff self-locking nerve catheter with a micron topological geometric structure in the middle and microneedle structures on both sides;

[0055] (6) When implanted in the body, the diameter of the selected catheter is slightly larger than the nerve. The two ends of the broken nerve are inserted into the catheter. The catheter is quickly heated and contracted by hot compress to effectively fix the nerve. The wound is then sutured.

[0056] Example 4

[0057] A thermosensitive rotator cuff self-locking nerve conduit with microneedles and micron topological geometric structures on the surface, the specific preparation of which includes the following steps:

[0058] (1) After fully mixing dimethylsiloxane monomer and crosslinking agent in a volume ratio of 10:1, the mixture is poured onto a cylindrical metal mold having microneedles and anisotropic micron topological structures on the surface, vacuum degassed for 1-2 hours, and then crosslinked in an oven at 60°C overnight. After fully curing, a PDMS columnar mold having a micron topological geometric structure in the middle and microneedle hole structures on both sides is obtained;

[0059] (2) Dissolve neurotrophic factors and curcumin at a concentration of 10-100 μg / ml in 3% chitosan solution, inject the two solutions into the pores of PDMS in sequence using a microsyringe, centrifuge at high speed for 5 min to ensure that the pores are completely filled, and air-dry to obtain the needle structure;

[0060] (3) Weigh 48 g of N-isopropylacrylamide (NIPA) and 0.6 g of N,N'-methylenebisacrylamide (BIS) in 100 ml of triple distilled water, and stir at room temperature until completely dissolved to obtain a precursor solution; dissolve 1 g of ammonium persulfate (APS) in 10 ml of triple distilled water to obtain a 10% initiator solution;

[0061] (4) Add 2 ml of initiator solution to 10 ml of precursor solution, add a concentric sleeve to the outside of the PDMS cylindrical mold, and quickly pour the mixed solution between the PDMS mold and the sleeve. After vacuum degassing, crosslink at 80 ° C for 1 h;

[0062] (5) slowly cooling in triple-distilled water, and after the temperature-sensitive catheter cools down and expands, the catheter is automatically removed from the mold to obtain a temperature-sensitive rotator cuff self-locking nerve catheter with a micron topological geometric structure in the middle and microneedle structures on both sides;

[0063] (6) When implanted in the body, the diameter of the selected catheter is slightly larger than the nerve. The two ends of the broken nerve are inserted into the catheter. The catheter is quickly heated and contracted by hot compress to effectively fix the nerve. The wound is then sutured.

[0064] Example 5

[0065] A temperature-sensitive rotator cuff self-locking nerve conduit with microneedles and micron-scale topological geometric structures on its surface, and its specific preparation includes the following steps:

[0066] (1) After thoroughly mixing dimethyl silicone monomer and cross-linking agent with a volume ratio of 10:1, pour the mixture onto a metal, polymer, or silicon wafer planar mold with microneedles and anisotropic micron-scale topological structures on its surface. After vacuum degassing for 1 - 2 h, cross-link overnight in an oven at 60 °C. After complete curing, a PDMS planar mold with micron-scale topological geometric structures in the middle and microneedle hole structures on both sides is obtained.

[0067] (2) Dissolve nerve growth factor and curcumin in 3% chitosan solution at a concentration of 10 - 100 μg / ml respectively. Use a micro syringe to inject the two solutions into the holes of the PDMS in sequence, and then centrifuge at high speed for 5 min to ensure complete filling of the holes. After air drying, a needle structure is obtained.

[0068] (3) Weigh 48 g of N-isopropylacrylamide (NIPA) and 0.6 g of N,N'-methylenebisacrylamide (BIS) and dissolve them in 100 ml of triple-distilled water by stirring at room temperature until completely dissolved to obtain a precursor solution. Dissolve 1 g of ammonium persulfate (APS) in 10 ml of triple-distilled water to obtain a 10% initiator solution.

[0069] (4) Add 1 ml of the initiator solution to 10 ml of the precursor solution, quickly pour the mixture onto the surface of the PDMS mold, and after vacuum degassing, cross-link at 80 °C for 1 h.

[0070] (5) Peel the scaffold from the mold, curl it into a tube along the topological direction, and fix it with glue to obtain a temperature-sensitive rotator cuff self-locking nerve conduit with micron-scale topological geometric structures in the middle and microneedle structures on both sides.

[0071] (6) When implanting in the body, select a conduit with a diameter slightly larger than the nerve. Insert the two ends of the severed nerve into both sides of the conduit, and use the method of hot compress to quickly heat and shrink the conduit to achieve effective fixation of the nerve. Then suture the wound.

[0072] Example 6

[0073] A temperature-sensitive rotator cuff self-locking nerve conduit with microneedles and micron-scale topological geometric structures on its surface, and its specific preparation includes the following steps:

[0074] (1) After thoroughly mixing dimethyl silicone monomer and cross-linking agent with a volume ratio of 10:1, pour the mixture onto a metal, polymer, or silicon wafer planar mold with microneedles and anisotropic micron-scale topological structures on its surface. After vacuum degassing for 1 - 2 h, cross-link overnight in an oven at 60 °C. After complete curing, a PDMS planar mold with micron-scale topological geometric structures in the middle and microneedle hole structures on both sides is obtained.

[0075] (2) Dissolve neurotrophic factor and curcumin in 3% chitosan solution at a concentration of 10 - 100 μg / ml respectively. Then, use a microsyringe to inject the two solutions into the holes of PDMS in sequence, and centrifuge at high speed for 5 min to ensure complete filling of the holes. After air drying, a needle structure is obtained.

[0076] (3) Weigh 48 g of N - isopropylacrylamide (NIPA) and 0.6 g of N,N’ - methylenebisacrylamide (BIS) and dissolve them in 100 ml of triple - distilled water at room temperature with stirring until completely dissolved to obtain a precursor solution. Dissolve 1 g of ammonium persulfate (APS) in 10 ml of triple - distilled water to obtain a 10% initiator solution.

[0077] (4) Add 2 ml of the initiator solution to 10 ml of the precursor solution, quickly pour it onto the surface of the PDMS mold, and after vacuum degassing, cross - link it at 80 °C for 1 h.

[0078] (5) Peel the scaffold from the mold, curl it into a tube along the direction parallel to the topology, and fix it with glue to obtain a temperature - sensitive rotator cuff self - locking nerve conduit with a micron - scale topological geometric structure in the middle and micro - needle structures on both sides.

[0079] (6) When implanted in the body, select a catheter with a diameter slightly larger than the nerve. Insert the two ends of the severed nerve into both sides of the catheter, and use hot compress to quickly heat - shrink the catheter to achieve effective fixation of the nerve. Then, suture the wound.

Claims

1. A preparation method of a temperature-sensitive rotator cuff self-locking nerve conduit, characterized in that, It includes the following steps: Prepare a PDMS mold with a micron topological geometric structure in the middle and micro-needle hole structures on both sides; Sequentially pour a natural or synthetic biomaterial containing drugs with nerve growth-promoting and anti-inflammatory functions into the micro-needle holes on the surface of the PDMS mold, and air-dry or crosslink and cure; Pour a temperature-sensitive hydrogel solution onto the surface of the PDMS mold, and form a biomaterial scaffold after crosslinking; Detach the crosslinked biomaterial scaffold from the PDMS mold to obtain a temperature-sensitive rotator cuff self-locking nerve conduit with a micron topological geometric structure in the middle and micro-needle structures on both sides.

2. The preparation method according to claim 1, wherein, The PDMS mold is prepared by a micro-molding method, and the material for preparing the PDMS mold is prepared by mixing dimethylsiloxane monomer and a crosslinking agent in a volume ratio of 10:

1.

3. The preparation method according to claim 1, characterized in that, A natural or synthetic biomaterial mixed with different drugs is sequentially poured into the micro-needle holes on the surface of the PDMS mold by a stepwise casting method.

4. The preparation method according to claim 1, characterized in that, The micron topological geometric structure is one or more array combinations of anisotropic micron grooves, micron concave holes, and micron protrusions; the micro-needle hole structure is one or several of a cone, a pyramid, and an arrow, and the micro-needles are arranged in one or more array combinations of uniform distribution or orientation along a specific direction.

5. The preparation method according to claim 1, characterized in that, The high part of the micron topological geometric structure is a ridge, and the low part is a groove. The vertical distance between the groove and the ridge is 2 - 10 μm, the width of the groove and the ridge is 10 - 50 μm, and the connection between the groove and the ridge is smooth or vertical; the height of the micro-needle is 100 - 1000 μm, the bottom diameter of the micro-needle is 100 - 200 μm, and the tip diameter is 30 - 50 μm.

6. The preparation method according to claim 1, characterized in that, The biomaterial used for the micro-needle is one or several of hyaluronic acid, methacrylated hyaluronic acid, chitosan, silk fibroin, collagen, polycaprolactone, and polylactic acid; the biomaterial used for the substrate of the biomaterial scaffold is one of poly(N-isopropylacrylamide) and poly(N,N-diethylacrylamide).

7. The preparation method according to claim 1, characterized in that, The nerve growth-promoting factor is one or several of nerve growth factor, ciliary neurotrophic factor, rapamycin, and reduced graphene oxide; the anti-inflammatory drug is one or several of triamcinolone acetonide, curcumin, and anthocyanin.

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